The influence of bituminous froth components on water-in-oil emulsion stability as determined by the micropipette technique

We have applied the micropipette technique of Yeung et al., Proc. Royal Soc. London A, 455 (1999) 3709, to study the effects which surface active constituents of bituminous froth have on the interfacial properties of various water-in-oil (W/O) emulsion systems in terms of interfacial tension and droplet coalescence. It is shown that asphaltenes play a dominant role in the stabilization of water droplets in diluted bitumen or froth. However, while asphaltenes appear to act as the primary stabilizer, other froth components are surface active and can influence W/O emulsion stability once the asphaltenes are removed. The micropipette technique is advantageous because visual observation of coalescence between individual water droplets can be a better indicator of changes in interfacial behaviour than interfacial tension measurements alone. This work is relevant to the better understanding of bituminous froth components and to the role of demulsifiers in displacing these components in order to induce water droplet coalescence.